Damage created in silicon by 1 MeV O+ ions as a function of beam power

Rutherford backscattering (RBS) and channeling of H+ and He+ particles were used to study the damage accumulation during 1 MeV O+ implantation in silicon. The beam current was varied between 0.2 and 3 μA, leading, in our experimental conditions, to a temperature rise up to about 400degC. The contributions of point and extended defects were separated using the energy dependence of the dechanneled fraction of particles passing through the disordered regions. Transmission electron microscopy observations have been performed in order to determine the dominant type of defect in a few cases. Mixing of points defects and partial dislocations was revealed for temperatures higher than 200degC. Their respective concentrations have been followed as a function of beam power and dose. Self-annealing and trapping are the dominant mechanisms pointed out. In the first microns, the residual amount of point defects per incident ion is shown to obey to an Arrhenius relation, with an activation energy of about 0.4 eV. Beam assisted regrowth of amorphous islands formed in the early stage of implantation is thought to occur. Unlike point defects, the formation of partials seems to be independent of temperature but only an effect of dose. (orig.)